I heard some legitimate questions about how to identify European
green crabs and what to do if you find one. The main thing is to
get a photograph and send it to the Washington Sea Grant Crab Team,
which is leading the war on green crabs. I’m reminded that it is
illegal to possess a green crab without a permit.

I’m also pleased to see the announcement of a free online
webinar on July 10 to help people identify European green crabs.
The two-hour “First Detector
Training Webinar” is co-sponsored by the Crab Team and
Washington Invasive Species Council. Register ahead of time to get
information about the event.

Nearly 100 invasive European green crabs were trapped along
Dungeness Spit near Sequim this past spring and summer — far more
than anywhere else in Puget Sound since the dangerous invaders
first showed up last year.

European green crabs started
showing up in traps on Dungeness Spit in April.Photo: Allen Pleus, WDFW

Despite the large number of crabs found in this one location,
green crab experts remain undeterred in their effort to trap as
many of the crabs as they can. And they still believe it is
possible to keep the invasion under control.

“In a lot of ways, this program is functioning much as we had
hoped,” said Emily Grason of Washington Sea Grant, who is
coordinating volunteers who placed hundreds of traps in more than
50 locations throughout Puget Sound. “We look in places where we
think the crabs are most detectable and try to keep the populations
from getting too large, so that they are still possible to
control.”

After the first green crabs were found on Dungeness Spit in
April, the numbers appeared to be tapering off by June, as I
described using a graph in
Water Ways on June 24. The numbers stayed relatively low, with
three caught in July, two in August, three in September and two in
October. But they never stopped coming.

The total so far at Dungeness Spit is 96 crabs, and more can be
expected when trapping resumes next spring. The good news is that
all the crabs caught so far appear to be just one or two years old
— suggesting that they likely arrived as free-floating larvae. That
doesn’t mean the crabs aren’t mating at Dungeness Spit, but the
trapping effort has reduced the population to the point that males
and females are probably having a tough time finding each
other.

Officials with the U.S. Fish and Wildlife Service, which has
taken charge of trapping at Dungeness Spit, will need to decide
whether to attempt a complete eradication of the local green crab
population, according to Allen Pleus, coordinator of Washington
State’s Aquatic Invasive Species Program. That would involve
managing a large number of traps until no more crabs are seen. The
alternative, he said, would be to manage the crab population with
fewer traps and make further decisions down the line.

During one three-day stretch last year, 126 traps were deployed
in areas on and near Dungeness Spit, part of the Dungeness National
Wildlife Refuge managed by the Fish and Wildlife Service.

Even with the most exhaustive trapping program, there is no
guarantee that green crabs won’t be found again, Allen said. The
likely source of the crab larvae is an established population of
green crabs in Sooke Inlet on Vancouver Island, just across the
Strait of Juan de Fuca from Dungeness Spit.

Allen said he is disappointed that crabs continued to be caught
on or near Dungeness Spit — mainly in one small area near the
connected Graveyard Spit. “But I am very impressed with the
dedication of the U.S. Fish and Wildlife Service, which continued
to trap throughout the summer,” he said.

While there is no evidence so far that the invading crabs have
reproduced at Dungeness Spit, it is possible that mating took
place. If so, everyone involved in the green crab effort could face
a whole new group of young crabs next year.

I have to admit that I was worried last spring that funding for
the essential volunteer effort would run out as officials scrambled
to finance the start of trapping season. But the Environmental
Protection Agency agreed to fund the project through next year
under the Marine and Nearshore Grant Program.

Meanwhile, Allen said he is working with Canadian officials to
see what can be done about reducing the population of green crabs
in Sooke Inlet, which is likely to remain a source of the invasive
crabs coming into Washington state. The Canadians have their own
concerns about green crabs, which can severely damage commercial
shellfish operations and disrupt critical eelgrass habitats.

“Sooke Inlet is the only known population established in the
Salish Sea,” Allen said. “We are working with Canada and setting up
meetings this winter to continue our discussions.”

Canadian officials are monitoring for green crabs on their side
of the border, but the effort is much less than in Puget Sound. It
appears that only limited efforts have been made so far to control
the Sooke Inlet population and reduce the amount of invasive crab
larvae heading to other areas in the Salish Sea.

Researchers are still investigating the conditions that allow
green crab larvae to survive long enough to grow into adult crabs.
It appears that larvae move up the coast from California during
warm years and particularly during El Niño periods, Emily told me.
That may explain why the Puget Sound traps began catching so many
crabs the past two summers.

“The signal we are seeing does point to 2015 and ‘16 as being
the first arrivals,” she said. “Our working hypothesis is that warm
years are spreading larvae.”

That could offer renewed hope for the immediate future, since El
Niño is over and we may be going into cooler La Niña conditions
next year.

No new crabs have shown up in the San Juan Islands, where Puget
Sound’s first green crab was discovered last year. But two more
were found about 30 miles away in Padilla Bay, where four crabs
were caught last fall.

New areas with green crabs this year are Lagoon Point on Whidbey
Island, where two crabs were caught, and Sequim Bay, not far from
Dungeness Spit, where one crab was caught.

The latest concern over green crabs is Makah Bay on the outer
coast of Washington near the northwest tip of the Olympic
Peninsula. In August, a beach walker spotted a single green crab on
the Makah Tribe’s reservation and sent a picture to the Puget Sound
Crab Team, which confirmed the finding. Tribal officials launched a
three-day trapping effort last month and caught 34 crabs — 22 males
and 12 females — in 79 traps.

An aggressive trapping effort is being planned by tribal
officials for the coming spring. Interested volunteers should
contact Adrianne Akmajian, marine ecologist for the Makah Tribe, at
marine.ecologist@makah.com

The Makah effort is separate from the Puget Sound Crab Team,
which encourages beach goers to learn to identify green crabs by
looking at photos on its website. Anyone who
believes he or she has found a green crab should leave it in place
but send photographs to the crab team at crabteam@uw.edu

Emily said she is most proud of all the people and organizations
that have come together as partners to quickly locate the invasive
crabs and advance the science around the issue. Such cooperation,
she said, makes the impact of the program much greater than it
would be otherwise.

Washington state property owners and people with swimming pools
are being urged to become part of a defensive initiative to protect
trees from invasive beetles.

August is National Tree Check Month, and at least four state
agencies are asking tree owners this month to take a 10-minute walk
around their property to look for insects that don’t belong in our
region.

Nationwide, more than a third of all insect invasions are first
detected by average people, according to Justin Bush, executive
coordinator of the Washington Invasive Species Council. Heading off
an invasion before it gets started could save untold millions of
dollars worth of trees, as well as the costs of battling a
spreading insect invasion.

This is the second year that Washington state agencies are
bringing the message home from other states where many longtime
tree populations have been decimated by insects, including the
citrus longhorned beetle and the emerald ash borer.

“While we don’t have these two invasive insects right now, we
could get them at any moment,” Justin told me. “We want people to
help us look for them.”

This year, state officials also are asking people who own
swimming pools and ponds to join in the defensive effort, as some
of invasive insects end up in the water and die. A swimming pool
owner or maintenance person should take note of any unusual insects
found in pool filters or among debris skimmed off the surface of
the water, he said. On the East Coast, swimming pool owners are
often able to spot invasive beetles even before they show up in
traps designed to attract them.

It would be helpful if people would look for invasive insects
all year long, Justin said, but August is a good time to place a
special emphasis on the effort, because this is the time that most
wood-boring insects emerge as adults.

Identifying specific species of beetles is often difficult,
Justin acknowledged. The best advice is to take pictures of the
insect from several angles and send the photos to the Invasive
Species Council, InvasiveSpecies@rco.wa.gov,
which will find an expert to identify the bug.

People shouldn’t hesitate to send photos, Justin said. “If it
comes to us, we can figure it out.”

Another reporting method is to download the “WA Invasives” app
to send photos and location data straight from your smart phone.
See WISC
download page. The app also includes photos and information for
identifying invasive species.

When emailing, one should include contact information, including
a phone number, along with the location of the insect sighting. (An
address or cross-street description would be helpful.) Details
about the tree species should be included as well.

If you obtain one of the beetles, you should keep it in case an
expert wants to inspect the specimen. Another option is to take the
beetle to a local office of WSU Extension, which can forward it to
appropriate experts.

The citrus longhorned beetle, a close relative of the disastrous
Asian longhorned beetle, is a major concern on the West Coast. The
beetle can feed on a variety of hardwood trees, including apple,
maple, oak, willow, alder and popular. When they emerge, they leave
an exit hole about 5/8-inch in diameter in the tree.

In 2001, the citrus longhorned beetle was found in Tukwila,
where it arrived in a shipment of bonsai trees. Three beetles were
recovered from the bonsai trees but five others were seen flying
away. Nearly 1,000 trees were cut and chipped within one-eighth
mile from the location site, and another 1,500 trees farther away
were treated with insecticide. The last beetle was seen in the fall
of 2002, and a quarantine remained in effect until 2006. See
U.S. Department of Agriculture website.

Because of heavy shipping from Asian ports, concerns remain high
that damaging beetles will be imported to the West Coast, Justin
said. Insects could also arrive from infested areas back East,
which is the primary route for European gypsy moths brought into
Washington state in moving vans. This state’s gypsy moth
eradication program — including nearly
100 local battles since 1979 (PDF 307 kb) — has kept the
damaging moths from establishing a permanent foothold in this
state.

Besides the citrus longhorned beetle, officials are concerned
that the emerald ash borer could devastate ash trees in this state.
The exit holes in ash trees are about a quarter-inch in diameter
and have a distinctive “D” shape. Ash trees are common in urban
areas, and the beetles apparently have been moving westward as
campers bring firewood from eastern areas. The beetle was recently
discovered in Boulder, Colo.

State agencies involved in the effort to track down the invasive
beetles are the Invasive Species Council, Department of
Agriculture, Department of Natural Resources and Washington State
University Extension.

The U.S. Department of Agriculture offers information on these
and other invasive insects:

State biologists are holding out hope that the European green
crab invasion at Dungeness Spit can be contained. We may now be
going through a critical period, which could result in a permanent
infestation or possibly the final throes of the invasion.

Green crabs, an invasive species known to displace native
species and cause economic devastation to shellfish growers, were
first discovered on April 12 in a marshy area on Graveyard Spit,
which juts off from the larger Dungeness Spit in the Strait of Juan
de Fuca.

The total number of green crabs caught in an ongoing intensive
trapping program has reached 76. The weekly numbers have been
declining, as shown in a chart on this page. That could be a good
sign, but biologists are quite reserved in their predictions.

“The numbers are tapering off,” said Allen Pleus, coordinator of
the state’s Aquatic Invasive Species Program, “but in my view the
numbers are still too high. Eradication would take several weeks of
zero. At this point, our main objective is to bring down the
population to a point where spawning would not be successful.”

So far, all of the crabs caught are young and small — about 1 to
2.5 inches across their backs. This means that they have not been
in the area for long, probably arriving on last year’s currents in
the Strait of Juan de Fuca.

Another good sign is that no other crabs have been caught
elsewhere along the Strait, although officials acknowledge that
they would like to deploy more traps to capture any early invaders.
Also, I am happy to report that no new crabs have been captured
this year in Padilla Bay or on San Juan Island, where the state’s
first confirmed green crab invasion took place last year. See
Water Ways, Sept. 24, 2016.

Update: I’ve been informed that one green crab was caught in
April in Padilla Bay where others were caught last year.

The decline in captures at Dungeness Spit may be a sign that
some of the crabs have entered their reproductive phase, a period
when they don’t eat and so are not attracted to the baited traps.
Males and females get together to mate after molting, a phase of
development in which they shed their exoskeletons. The trapping
effort has reduced the crab numbers and made it more difficult for
reproductive males and females to find each other, but each female
can produce hundreds of thousands of eggs — so even one successful
mating could expand the invasion.

This small male crab is one of
the 76 European green crabs caught in traps at Dungeness Spit. //
Photo: Allen Pleus

Because the baited traps may not work at this time, officials
are experimenting with substrate traps, which are pieces of plastic
pipe ranging in size from a half-inch to 2 inches, Allen told me.
Young crabs may seek shelter in the tubes. So far, no crabs have
been captured that way.

Another idea yet to be tried is baiting traps with pheromones,
which are sexual attractants that lure crabs looking for a mate.
Allen said he also would like to experiment with electrical
stimulation, in which an electrical current is discharged in the
muddy substrate to drive crabs out of their burrows. With proper
control, no permanent harm comes to them or other creatures in the
vicinity, Allen said.

When it comes to controlling future crab invasions in Puget
Sound, experts would like to know where the crab larvae are coming
from. The leading suspect is a population of green crabs that
appear to have settled into Sooke Inlet, just west of Victoria on
Vancouver Island in Canada. It is also possible that the larvae
drifted in from coastal waters in British Columbia, Washington or
even Oregon or California. Experts hope that genetic tests of green
crabs from the various locations can be used to identify where the
crabs on Dungeness Spit originated.

Emily Grason of Washington Sea Grant coordinates a group of
volunteers who monitor traps placed throughout Puget Sound with a
goal of stopping the next invasion.

“The presence of green crab in Dungeness Bay, though
unfortunate, offers a unique opportunity to test how effective the
EDRR (Early Detection-Rapid Response) model is for intervening in a
potential green crab invasion,” Emily wrote yesterday in a blog
post on the Crab
Team website.

“Generally speaking, invasive species are rarely noticed in a
new spot until they have already become too abundant to eradicate,”
she said. “Though 76 crabs at Dungeness Spit is more than we would
ever like to see, the population hasn’t yet reached the numbers
that are seen in areas of greatest infestation. And they are, as
far as we know, still confined to a relatively small location….

“Preventing and managing biological invasions is similar to
planning for a wild fire season: The best thing to do is prevent
either invasions or wildfires from taking hold in the first place,
but we know that some will occur despite our best efforts. It’s
difficult to forecast exactly where, when or how severe they will
be when they do pop up, and yet it’s imperative to respond quickly
and aggressively as soon as they are detected.”

Emily added that we are fortunate in this area to have the
tremendous support of volunteers, partners and beachgoers, all
involved in the effort to prevent a permanent invasion of green
crabs. Staff and volunteers at the Dungeness National Wildlife
Refuge have been instrumental in placing and tending the traps
placed in that area.

An invasion of the European green crab, which started last
summer in northern Puget Sound, appears to be continuing this
spring with 16 green crabs caught in traps at one location on
Dungeness Spit near Sequim.

European green crabPhoto: Gregory C. Jensen, UW

The new findings are not entirely unexpected, given that
invasive green crabs have established a viable population in Sooke
Inlet at the southern end of Vancouver Island in Canada. From
there, young crab larvae can move with the currents until they
settle and grow into adult crabs. Last summer and fall, green crabs
were found on San Juan Island and in Padilla Bay.

The big concern now is that a growing population of invasive
crabs could spread quickly to other parts of Puget Sound, causing
damage to commercial shellfish beds and disrupting the Puget Sound
ecosystem.

“It knocks the wind out of your sails for sure,” said Emily
Grason when I asked how she felt about the latest discovery. “You
feel kind of powerless, and you want to get out there and start
doing things.”

A European green crab invasion may be taking place in Puget
Sound, and Washington Sea Grant intends to enhance its Crab Team
this summer with more volunteers looking in more places than ever
before.

The second European green crab
identified in Puget Sound was found in Padilla Bay, where three
others were later trapped.Photo: Padilla Bay Reserve

Training is about to get underway, and anyone with an interest
in furthering science while being exposed to the wonders of nature
may participate. It’s not always good weather, but I’ve been
inspired by the camaraderie I’ve witnessed among dedicated
volunteers.

The work involves going out to one or more selected sites each
month from April into September with a team of two to four other
volunteers. It is helpful to have folks who can carry the crab
traps, plastic bins and other equipment. For details, check out the
Washington Sea Grant website.

Invasive species from San Francisco Bay — known as the most
infested waterway in the country — would have an open door for
entry into Puget Sound under a bill moving through Congress.

Ballast discharge from a
shipPhoto: Coast Guard

You may have heard this line before. I posted the same warning
last summer, when the Vessel Incidental Discharge Act, or VIDA, was
attached to the “must-pass” National Defense Authorization Act.
(Water
Ways, July 16). Opponents fought back and were able to strip
VIDA from the bill before final passage.

Now, with Republicans in control of both houses of Congress and
an anti-regulatory atmosphere in place, the bill’s passage seems
more likely this time — to the detriment of Puget Sound, the Great
Lakes and other waterways.

If VIDA passes, ships coming up the coast from California will
be able to take on infested ballast water in San Francisco Bay and
discharge it without treatment into Puget Sound. Invasive species
that hitched a ride in the ballast water would have a chance to
populate Puget Sound.

Invasive saltwater snails, including dreaded oyster drills, seem
to be far more leery of predators than native snails under certain
conditions, according to a new study by Emily Grason, whose
research earned her a doctoral degree from the University of
Washington.

Why non-native snails in Puget Sound would run and hide while
native species stand their ground remains an open question, but the
difference in behavior might provide an opportunity to better
control the invasive species.

Of course, snails don’t actually run, but I was surprised to
learn that they can move quite rapidly to find hiding places when
they believe they are under attack.

Like many marine animals, snails use chemical clues to figure
out what is happening in their environment. For her experiments,
Emily created a flow-through system with two plastic shoeboxes.
Chemical clues were provided in the upstream bin, while the
reaction of the snails was observed in the downstream bin.

The most dramatic difference between native and non-native
snails seemed to be when ground-up snails were deposited in the
upstream bin, simulating a chemical release caused by a crab or
other predator breaking open snail shells and consuming the tender
morsels inside.

Padilla Bay, an extensive inlet east of Anacortes in North Puget
Sound, could become known as an early stronghold of the invasive
European Green crab, a species dreaded for the economic damage it
has brought to other regions of the country.

Trapping sites for crabs (gray
markers) during this week’s rapid assessment in Padilla Bay. Red
markers show locations where three more invasive European green
crabs were found.Map: Washington Sea Grant

After one young green crab was found in Padilla Bay on Sept. 19
(Water
Ways, Sept. 24), three more crabs were found during an
extensive trapping effort this past week. All four crabs were
captured at different locations in the bay. These four live crabs
followed the finding of a single adult green crab in the San Juan
Islands — the first-ever finding of green crabs anywhere in Puget
Sound. (Water
Ways, Sept. 15).

With these new findings in Padilla Bay, the goal of containing
the crabs to one area has become a greater challenge. Emily Grason,
who coordinates a volunteer crab-surveillance program for
Washington Sea Grant, discusses the difficulty of putting out
enough traps to cover the entire bay. Read her report on the
fist day of trapping:

“Similar to our trip to San Juan Island, we are conducting
extensive trapping in an effort to learn more about whether there
are more green crabs in Padilla Bay. One difference, however, is
scale. Padilla Bay is massive, and it’s hard to know exactly where
to start. On San Juan Island, the muddy habitats where we thought
crabs would do well are well-defined, and relatively limited.
Padilla Bay, on the other hand, is one giant muddy habitat — well,
not all of it, but certainly a huge portion. We could trap for
weeks and still not cover all of the suitable habitat!”

In all, 192 traps were set up at 31 sites, covering about 20
miles of shoreline. The crab team was fortunate to work with the
expert staff at the Padilla Bay National Estuarine Research
Reserve, a group of folks who know the area well and had worked
with shoreline owners to get approval for access.

Three of the four green crabs caught in Padilla Bay were young,
probably washed into the bay during last winter’s warm currents,
Emily said in her wrap-up
report of the effort.

“All of the detections of European green crabs occurred on the
east portion of the bay,” she wrote. “Though the sites varied
somewhat in the type of habitat, all of the crabs were found
relatively high on the shore, in high salt marsh pools, or within a
few meters of the shore.

The first of four European
green crabs found in Padilla Bay.Photo: Padilla Bay National Estuarine
Reserve

“Padilla Bay has about 20 miles of shoreline, and, at last count
in 2004, there were 143 acres of salt marsh habitat in the bay,”
she continued.”These numbers suggest that there are a lot of places
European green crabs could live in Padilla Bay, and protecting the
bay from this global invader will undoubtedly require a cooperative
effort.”

Yesterday, the response team held a conference call to discuss
what to do next. Team members agreed that no more intensive
trapping would take place this year, Sean McDonald of the
University of Washington told me in an email.

Winter is a tough time to catch crabs. Low tides shift from
daytime hours to nighttime hours, making trapping more difficult.
Meanwhile, crabs tend to lose their appetite during winter months,
so they are less likely to go into the traps to get food, experts
say.

Researchers, shellfish growers and beach walkers are being asked
to stay alert for the green crabs, not only in Padilla Bay but also
in nearby Samish and Fidalgo bays.

The Legislature will need to provide funding to continue the
citizen science volunteer monitoring program, which provided an
early warning that green crabs had invaded Puget Sound. Whether the
crabs will survive and in what numbers is something that demands
more study and perhaps a major eradication effort.

Meanwhile, Washington Department of Fish and Wildlife would like
to expand its overall Aquatic Invasive Species Program with
additional efforts to prevent invaders from coming into Puget
Sound. For information, check out my story on invasive species in
the Encyclopedia
of Puget Sound — specifically the section titled “Biofouling
still mostly unregulated.”